Epiphakic intraocular lens and process of implantation

ABSTRACT

In one implantation process, the intraocular lens implant is placed partially or completely on the anterior capsular surface of the human crystalline lens and is attached thereto by means of glue or adhesive. The implant has overall edge-to-edge dimensions such that it does not extend beyond the periphery of the human lens. In several embodiments, adhesive receiving wells are formed in the implant lens near the periphery to facilitate attachment of the implant lens to the human lens. In another embodiment, the implant lens has structure extending from its posterior side for engaging the human lens to space the implant lens from the human lens. In still another embodiment the posterior side of the implant lens is vaulted such that the central portion of the implant lens does not engage the human lens. 
     In another implantation process, the intraocular lens is attached to a previously implanted intraocular lens for optical correction purposes. Attachment may be with adhesives or mechanical means such as clips.

This application is a continuation of U.S. patent application Ser. No.07/494,762 filed on Mar. 16, 1990, now U.S. Pat. No. 5,098,444.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to artificial intraocular lens implants for thephakic or pseudophakic human eye.

2. Description of the Prior Art

It is well known that there are many ways the human eye can deviate fromthe optical ideal of emmetropia, in which images are precisely focusedon the retina naturally, without assistance or effort, resulting inclear vision requiring no additional optical correction. Such deviationsfrom the optical ideal of emmetropia which produce an opticallynon-ideal situation, or ammetropia, include:

1. Myopia (near-sightedness)--in which the image of the object of regardis focused in front of the retina producing a blurry image on the retinaitself.

2. Hyperopia (far-sightedness)--in which the image of the object ofregard is focused behind the retina producing a blurry image on theretina itself.

3. Astigmatism (asymmetry or irregularity of cornealcurvature)--producing an irregular and therefore blurry image.

4. Presbyopia--loss of the accommodative ability of the naturallyoccurring human crystalline lens, making near objects blurry.

5. A combination of the above.

The presence of these optically aberrant or ammetropic conditions is dueto a relative mismatching of the optical powers of the optical elementsof the eye (primarily the cornea and lens) with respect to the positionof the retina, which produces a failure of the eye as an optical systemto function in the desired manner to give clear vision. This can occurin spite of the otherwise normal condition of the tissues of the opticalelements involved.

Many methods have been developed in an attempt to correct the abovementioned group of naturally occurring ammetropic conditions of myopia,hyperopia, astigmatism, and presbyopia including:

1. Spectacle correction--in which refracting lenses in glasses framesare positioned in front of the eye, external to, and not in contact withthe cornea.

2. Contact lenses--which physically rest upon the external surface ofthe cornea and its tear film and alter the overall optical status of theeye by means of their refractive optical power and also by the physicalpresence on the corneal surface thereby neutralizing irregularities ofthe corneal surface. A technique known as orthokeratology has beendeveloped in which the shape of the cornea is modified by fitting acontact lens having a particular desired curvature which is intended tochange the shape of the cornea to the curvature of the contact lens.This technique has had minimal success due to the nonpermanent nature ofthe induced curvature change on the cornea by the contact lens, and ispracticed little today.

3. Refractive surgery--in which the optical refractive status of the eyeis altered through some surgical procedure. One general group ofprocedures is referred to as corneal refractive surgery in which achange in the corneal shape, or refractive index, or both, is surgicallyinduced, thereby changing the corneal optical power. Examples of cornealrefractive surgery are:

A. Radial keratotomy--(developed initially by Sato in Japan in 1939 andmore recently popularized by S. N. Fyodorov in Russia and brought to theU.S. by Bores) in which radial incisions are made into the substance ofthe corneal tissue changing its shape. This procedure, along with manyvariations in the orientation, length, number and depth of incisions,has been used to correct myopia, astigmatism, and more recentlyhyperopia.

B. Keratophakia (originated by Jose Barraquer--Bogota, Colombia) and itsvariations such as epikeratoplasty (developed by Kaufman andMacDonald)--in which properly preshaped human donor tissue is surgicallyplaced on the external surface of the cornea, thereby altering theoverall corneal shape and consequently its refractive effect.

C. Keratomileusis--(originated by Barraquer, Colombia) in which thepatient's surface corneal tissue is removed, reshaped in some fashion atsurgery, and replaced on the corneal surface in its new configuration.

D. Synthetic corneal onlay--in which a synthetic material (silicone orhydrogel-like material) is placed directly onto the corneal surface,thereby altering the corneal shape.

E. Synthetic corneal inlay--(developed by Peter Choyce)--in which apocket is surgically developed within the layers of the corneal tissueinto which is slid or placed a polysulfone disc which, by its higherrefractive index than the surrounding normal corneal tissue, alters theoverall optical power of the cornea. Note U.S. Pat. No. 4,624,669.Another type of corneal inlay procedure is also under developmentnotably by Dr. Theodore Werblin in which the surface corneal tissue isremoved centrally and a refractive disc (which is made of syntheticsilicone-like or hydrogel-like materials)is placed within this bed,after which the previously removed corneal tissue is replaced over theinlay. The inlay is consequently "sandwiched" between the previouslyremoved anterior corneal surface tissue in front and the posteriorcorneal tissue behind, and has its effect, unlike the inlay of Choyce,primarily by means of changing the corneal curvature.

F. Corneal laser sculpting--in which by means of the application oflaser energy (notably currently eximer laser energy) to the cornealtissue, the cornea is reconfigured by means of incisions (as in radialkeratotomy) or reshaped (sculpted) to alter its configuration.

Another general type of refractive surgery has been directed towardaltering the length of the eye by means of scleral resection or support,generally intending to shorten the anterior/posterior ocular length inlong, highly myopic eyes. This surgery is extremely complex, dangerous,and generally ineffective and has fallen into disuse.

A different surgical approach in highly myopic eye has been recentlyadvocated by Verzella in which the clear (noncataractous) lens isremoved, leaving the eye aphakic. Because of the loss of the opticalconverging power of the naturally occurring human lens, the eye isrendered less myopic. Some have advocated the removal of the naturallens and replacement with an intraocular lens of less convergent power,which also makes the eye less myopic.

Cataract removal, particularly with the advent of intraocular lenses,must technically also be considered a type of refractive surgery.However, it differs considerably from the previously describedprocedures in that the eye, specifically the optical element--the humanlens, is not normal, but is cataractous. The eye may in fact beotherwise emmetropic. The cataract surgery is performed expressly forthe purpose of removal of the cataract for vision improvement. Theintraocular lens is implanted for optical correction of the eye whichnow requires optical correction only because the cataractous lens hasnow been removed.

Also, technically, the surgery of keratoprosthesis implantation is arefractive procedure in which an optical element with a surroundingstabilizing element is implanted (imbedded actually) in the tissue ofthe cornea into which it finally becomes an integral part. Thisprocedure, however, is reserved for the most desperate of situations inwhich usually the corneal tissue is markedly scarred and opaque andthere is little if any hope of successful visual rehabilitation with anyother surgical approach.

Another surgical procedure for altering the refractive status of theammetropic usually myopic but otherwise healthy, phakic eye has been theimplantation of an intraocular lens within the phakic eye, virtuallyexclusively in the anterior chamber. This particular location has beenused in order to avoid physical contact between the intraocular lens andthe normal human lens which might result in traumatic damage to thehuman lens and possibly cataract formation. In the late 1940's and early1950's, when this type of procedure was first attempted, complicationsfrom these anterior chamber implants such as chronic inflammation withinthe eye (iritis), corneal swelling and cloudiness, glaucoma, andcataracts did indeed occur. These complications were the result both ofpoor intraocular lens: designs (which resulted in implant being tooclose to the cornea, particularly peripherally, and to the human lenscentrally), materials and manufacture. The complication rates of theseearly anterior chamber implant procedures were so high and the resultswere so poor that the procedure was abandoned.

With our improved understanding of intraocular lens biopathology, lensdesigns, materials and manufacturing techniques, the procedure ofanterior chamber intraocular lens implantation in phakic eyes hasrecently been resurrected with modern anterior chamber intraocular lensimplants. These phakic implants have been implanted virtuallyexclusively in the anterior chamber to avoid the previously mentionedcomplications of iritis, corneal swelling and decompensation, glaucoma,and especially cataract, all of which as mentioned, have beenencountered before. The anterior chamber is the location which affordsthe greatest separation between the implanted intraocular lens and thehuman lens. This principle of maximum separation between the intraocularlens implant and the human lens has been reinforced by the recentdevelopment of anterior chamber implants for refractive correction ofphakic eyes which have a greater anterior vault or angulation thananterior chamber implants used for cataract surgery. This greaterangulation, however, has the considerable disadvantage of placing theimplant closer to the cornea risking corneal touch with resultantdamage, eventual swelling and decompensation.

A final method of refractive correction in the r phakic eye has beendescribed by Mazzocco (U.S. Pat. No. 4,573,998) Blackmore (U.S. Pat. No.4,585,456), and Kelman (U.S. Pat. No. 4,769,035) in which it is proposedthat the optically corrective device be placed directly on thecrystalline lens of the eye. This general concept of placement of theoptical device directly upon the crystalline lens places the implant asfar as possible from the delicate structures of the cornea, specificallythe endothelium, which is a distinct advantage over phakic implantsplaced in the anterior chamber. The particular design of Mazzoccospecifically addresses a method of implantation comprising a series ofsteps including an intraocular lens having a deformable optical portionwhich must be compressed to about 80% or more of the cross-sectionaldiameter prior to insertion into the eye. The compressible implant isdescribed as having various mechanisms of fixation, which include: 1.Suturing to the iris anteriorly by means of a suture passed through theiris and through openings located in the periphery of the implant device(FIGS. 9, 10, 21, 21a, 22, 22a in the Mazzocco U.S. Pat. No. 4,573,998),or 2. By means of peripheral fixating members which hold the implant inposition through physical contact and pressure upon the tissues of theperiphery of the eye, either in the anterior chamber in the angle (FIGS.11, 12, 15-20, 23,24, 25, 26 in the Mazzocco U.S. Pat. No. 4,573,998),or more pertinent to the discussion here, in the posterior chamber,peripheral to the lens and posterior to the iris in the ciliary sulcus(FIG. 60 in Mazzocco patent). Therefore, although the proposed opticallycorrective implant devices of Mazzocco are proposed to lie upon thehuman crystalline lens, they obtain their fixation from a location otherthan the human crystalline lens, namely the angle (anterior chamber),iris, or the ciliary sulcus (posterior chamber). Note also Blackmore(U.S. Pat. No. 4,585,466) and Kelman (U.S. Pat. No. 4,769,035).

To summarize, the corneal refractive procedures are;

1. Incisional reshaping (surgical knife or laser)--such as radialkeratotomy.

2. Corneal onlays.

A. Human donor tissue--keratophakia, epikereatoplasty.

B. Reshaped patient's tissue--keratomileusis.

C. Synthetic material.

3. Corneal inlays

A. Polysulfone--refractive index change effect.

B. Silicone or hydrogel--configuration change effect (mainly).

4. Laser corneal reshaping.

5. Keratoprosthesis implantation.

6. Scleral resection--no longer widely used.

7. Lensectomy

A. Clear lensectomy (either alone or with implantation of a low powerIOL)

B. Cataract extraction with IOL implantation.

8. Phakic IOL implantation--uses anterior chamber IOL (modified withgreater anterior vault)

9. IOL placed on the anterior surface of the iris or anterior surface ofthe lens and held in position by peripheral fixation members.

With particular reference to the compressible IOL described by Mazzocco,it should be noted that the various mechanisms of fixation he proposesfor stabilization of the implant (anterior chamber angle, iris andciliary sulcus) are well known to be less biocompatible (and thereforeless acceptable) when they have been utilized for fixation ofintraocular lenses which have been implanted after cataract extraction.It is reasonable for anyone skilled in the art to deduct from thisprevious clinical experience with intraocular lenses implanted aftercataract extraction, that these mechanisms of fixation would besimilarly less biocompatible and therefore less desirable in anyintraocular lens implant device placed within the eye directly upon thecrystalline lens.

This is a particular concern since it is anticipated that surgicaloptical refractive correction would be attempted in a patient populationgenerally considerably younger than the population in which cataractextraction is common. Therefore, it would be expected that a youngerpatient would require a longer lifetime of intraocular acceptance fromsuch an implant. This increased lifetime expectancy puts an even greaterdemand on any phakic implant design to be maximally biocompatible, and acrucial feature of any phakic implant design is its fixation mechanism.A maximally biocompatible fixation mechanism is essential to ensurelong-term ocular acceptance of any phakic implant. Clearly, the morerigorous design requirements cf a phakic implant eliminate thepreviously proposed fixation mechanisms of Mazzocco, Blackmore, andKelman of anterior chamber angle, iris, or ciliary sulcus fixation asacceptable options. Unfortunately, the fixation mechanism which has beenfound to be most biocompatible for intraocular lenses implanted aftercataract extraction, namely, fixation within the capsular bag, is notavailable for phakic implant fixation since the human crystalline lensremains intact.

This overall situation, therefore, leaves the questions of a suitablybiocompatible fixation mechanism for a phakic implant which physicallyrests partially or completely on the human crystalline lens unansweredby the prior art.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a fixation process for aphakic implant which physically rests partially or completely on theanterior (capsular) surface of the natural human lens (hereinafterreferred to as an epiphakic implant) wherein the epiphakic implant isfixated directly to the anterior capsular surface of the human lens.

It is another object of the invention to provide an epiphakicintraocular lens implant structured such that it may be fixated directlyto the anterior capsular surface of the human lens.

It is a further object of the invention to provide an intraocular lensimplant for refractive correction of the phakic eye that is placedpartially or completely on the anterior capsular surface of the humancrystalline lens (epilentricular implant) and is attached thereto bymeans of gluing or adhesion. The implant device has overall edge-to-edgedimensions such that the implant does not overlap, or overlaps onlyminimally, the zonular attachments to the human lens. The edge peripheryhas optimally thin, smooth and posteriorly located edges to minimizemechanical contact and damage to the adjacent iris.

Rather than depending on angle, iris or ciliary sulcus fixation, theepiphakic intraocular lens implant is fixated by "gluing" (or makingotherwise adherent) the implant directly to the anterior capsularsurface of the lens. This mechanism of fixation has the advantage ofrelying on the relatively nonreactive and durable anterior capsule ofthe human crystalline lens, thereby avoiding contact with the moredelicate, reactive and less tolerant tissues of the angle of theanterior chamber, the iris, or ciliary sulcus. Eliminating the need forcontact with these structures for fixation represents a superior andmore biocompatible fixation mechanism.

In several embodiments, adhesive receiving "wells" or receptacle sitesare formed in the implant lens near the periphery to facilitateattachment of the implant lens to the human lens. In another embodiment,the implant lens has structures extending from its posterior side orsurface for engaging the human lens to space the implant lens from thehuman lens. In still another embodiment the posterior side of theimplant lens is vaulted such that the central portion of the implantlens does not engage the human lens.

The above process also has application in altering or correcting theoptical power of an artificial intraocular lens previously implanted inthe eye after removal of the human (usually cataractous) lens. In somecases, optical alteration or correction of the previously implantedartificial lens is necessary and desirable, however, surgical removal ofthe already implanted lens may be technically difficult and dangerousand correction cannot be made by removal and replacement of thepreviously implanted artificial intraocular lens.

Accordingly, it is an object of the invention to attach a secondartificial intraocular lens to the first implanted artificialintraocular lens for optical correction purposes. Attachment can be madewith adhesive or with mechanical means.

The second artificial intraocular lens may have adhesive receiving"wells" or receptacle sites near its periphery or peripheral clips forattaching the second artificial intraocular lens to the firstintraocular lens.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an intraocular lens of one embodiment of theinvention showing its anterior side.

FIG. 2 is an enlarged cross-sectional view of FIG. 1, taken along thelines 2--2 thereof.

FIG. 3 is an enlarged cross-sectional view of the lens of FIG. 1 showinga modification thereof.

FIG. 4 is a plan view of an intraocular lens of another embodiment ofthe invention showing its anterior side.

FIG. 5 is a cross-sectional view of the lens of FIG. 4 showing theinjection of a glue or adhesive through the opening to the posteriorside thereof.

FIG. 6 is a plan view of an intraocular lens of another embodiment ofthe invention showing its posterior side.

FIG. 7 is an enlarged cross-sectional view of the lens of FIG. 6.

FIG. 8 is a cross-sectional view of the human eye showing one of thelenses of FIGS. 1-6 with its posterior side seated and "glued" againstthe anterior surface of the natural lens of the human eye. In this viewthe openings, wells, or channel of the artificial lens are not shown.

FIG. 9 is a front view of the human eye with the lens of the inventionon the anterior surface of the human eye.

FIG. 10 is a partial cross-sectional view of a portion of an intraocularlens with a suboptimal edge profile with a rounded but thick peripheraledge.

FIG. 11 is a partial cross-sectional view of a portion of an intraocularlens with a suboptimal edge profile with a thin peripheral edge but withthe peripheral edge too anterior.

FIG. 12 is a partial cross-sectional view of a portion of an intraocularlens with the peripheral edge near the posterior surface and rounded.

FIG. 13 is a cross-sectional view of an intraocular lens having anoptimal edge profile with the peripheral edge posteriorly placed as inFIG. 12

FIG. 14 is a cross sectional view of an artificial intraocular lens ofanother embodiment of the invention with "feet" extending from itsposterior side.

FIG. 15 is a partial cross-sectional view of the human eye theintraocular lens of FIG. 14 elevated off of the anterior surface of thehuman lens by the "feet" leaving a space between the intraocular lensand the human lens.

FIG. 16 is a plan view of an intraocular lens of another embodiment ofthe invention having a permeable central optical portion surrounded byand joined to an appropriate carrier ring.

FIG. 17 is a cross-sectional view of another embodiment of the implantlens of the invention wherein the central portion of the posterior sideof the lens is vaulted sufficiently to provide a space between thisportion and the anterior capsular surface of the human lens.

FIG. 18 illustrates the lens of FIG. 17 seated and glued against theanterior surface of the natural lens of the human eye.

FIG. 19 is a cross-sectional view of an implant lens similar to that ofFIGS. 17 and 18 but modified.

FIG. 20 is a plan view of an artificial intraocular lens with hapticssimilar to that described in U.S. Pat. No. 4,418,431.

FIG. 21 is a partial cross-sectional view of a human eye having thenatural lens removed and the lens of FIG. 20 implanted in the anteriorchamber.

FIG. 22 is a partial cross-sectional view of a human eye having thenatural lens removed and the lens of FIG. 20 implanted in the posteriorchamber with its fixation members or haptics in the ciliary sulcus.

FIG. 23 is a partial cross-sectional view of a human eye having thenatural lens removed and the lens of FIG. 20 implanted in the posteriorchamber with its fixation members or haptics in the posterior capsularbag.

FIG. 24 is a cross-sectional view of an artificial intraocular lensseated on and attached to the anterior surface of the optic of apreviously implanted artificial intraocular lens, and having curvaturefor myopic correction.

FIG. 25 is a cross-sectional view of an artificial intraocular lensseated on and attached to the anterior surface of the optic of apreviously implanted artificial intraocular lens and having curvaturefor correction of hyperopia.

FIG. 26 is a cross-sectional view of an artificial intraocular lenshaving diffraction optics for bifocal or multifocal correction seated onand attached to the anterior surface of the optic of a previouslyimplanted artificial intraocular lens. It is to be understood that thediffraction ridges could be located on the posterior side of theepiphakic implant.

FIG. 27 is a plan view of an artificial intraocular lens seated on theoptic of a previously implanted artificial intraocular lens.

FIG. 28 is a cross-sectional view of an artificial intraocular lensseated on the anterior surface of the optic of a previously implantedartificial intraocular lens and having clips for holding the lens inplace to the previously implanted lens.

FIG. 29 is a cross-sectional view of an artificial intraocular lensseated on the anterior surface of the optic of a previously implantedartificial intraocular lens and having clips and pegs for holding thelens in place to the previously implanted lens.

FIG. 30 is a cross-sectional view of artificial intraocular lens seatedon the anterior surface of the optic of a previously implantedartificial intraocular lens and held in place by pegs and flangesextending through holes formed through the previously implanted lens.

FIG. 31 is a cross-sectional view of an artificial intraocular lensresting peripherally on the optic of a previously implanted artificialintraocular lens with a central space between the two optics.

In FIGS. 24-31 the haptics of the previously implanted artificialintraocular lens are not shown for purposes of clarity.

FIG. 32 illustrates an artificial intraocular lens attached by clips tothe haptics of a previously implanted artificial intraocular lens.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1 and 2, the artificial intraocular lens shown isidentified by reference numeral 21 and comprises a transparent opticalmember 23 having an optical axis 25 and anterior and posterior sides 27and 29 respectively transverse to the optical axis and extending outwardfrom the optical axis to a peripheral edge 31. Preferably the lens iscircular in shape when seen in a plan view although it could beelliptical, triangular, square, or have other shapes as desired. Formedthrough the lens 21 near the peripheral edge 31 are four wells oropenings or receptacle sites 33 which extend between sides 27 and 29.Located in the wells 33 is an energy labile (such as thermolabile)adhesive 35. The posterior side 29 of the lens may be shaped to conformto the anterior surface 43-1 of the human lens as shown in FIG. 8although alternately the posterior side 29 may be shaped as described inconjunction with FIGS. 17-19 as will be described subsequently In FIG.8, reference numerals 41 identify the cornea; 43 the human lens; 45 theciliary process; and 47 the zonule and 49 the iris. For maximalbiocompatibility, the maximal overall edge-to-edge dimension (diameterwhen the implant lens is completely circular) should be sufficientlysmall so that the peripheral edges of the implant lens extend minimally,if at all, onto the zonular attachments to the anterior lens capsuleperipherally. This is important so that the implant lens remains inposition on the anterior surface of the human crystalline lens centralto the central most portion of the zonular attachments to the lenscapsule, thereby avoiding possible damage to the zonules which mightresult in zonular breakage and eventual dislocation of the humancrystalline lens. The size of the implant lens 21 is chosen not only toremain central to the zonules but to remain larger than the pupillaryspace under usual conditions of bright and dim illumination (for mostpatients). It is anticipated this would require overall edge-to-edgedimensions to be no greater than approximately 5 to 6 mm but possibly ashigh a:: 6.5 to 7.0 mm. In FIG. 9, reference numerals 43-2 representsthe margin of the human lens (peripheral edge); 45 the ciliaryprocesses; 47 the zonules extending from the ciliary body to theanterior surface of the human lens; 31 the peripheral edge of theimplant lens; 49-1 the pupillary margin (central edge of the iris; and51 the limbus. In FIG. 9, the central iris border is represented at 49-1but the remainder of the peripheral iris is treated as transparent inorder to demonstrate the anatomical structures behind the iris, namely:the implant lens 21, the human lens, the ciliary processes, and thezonules.

In order to employ a lens 21 of the proper shape and dimensions,pre-measurements will be made of the human lens to determine the maximumdimensions of the implant lens 21 and the curvature of the posteriorside 29 of the implant.

In the implantation process, an incision 61 (FIG. 8) is made through thelimbus 51 of the eye of a sufficient size such that the implant lens 21may be inserted through the incision into the eye with the posteriorside 29 of the lens 21 seated against the anterior surface 43-1 of thehuman lens in optical alignment with the human lens and with the lensimplant located centrally to the central most portion of the zonularattachments to the human lens capsule. The glue or adhesive 35 in the"wells" 33 is then subjected to a source of energy such as a laser beamfrom an argon laser, thereby altering the thermolabile glue materialcausing it to adhere and to adhere the implant lens to the underlyinghuman lens capsule. This will represent a very localized reaction withvirtually no significant damage to the underlying human lens tissue. Thewells containing the glue 35 may be present in various locations andconfigurations as is determined optimal for complete and satisfactoryfixation of the implant lens 21 to the human lens wherein the implantlens is rendered completely immobile.

In FIG. 3 the lens 21 of FIGS. 1 and 2 has been modified in that theopenings or wells 33-1 do not extend completely through the lens buthave a thin covering or wall 27-1 on the anterior side to preventexposure of the glue or adhesive 35 to the iris. In the embodiment ofFIG. 3, the openings or wells 33-1 extend from the posterior side of thelens 21 to the wall 27-1. In this embodiment a laser or other energysource also will be employed to cause the glue to adhere and to attachthe implant lens to the underlying human lens capsule. As analternative, the "wells" 33-1 may have a thin wall on the posterior sideof the lens 21. The "wells" 33-1 are filled with adhesive 35 from theanterior side and the posterior thin walls are energy labile whereby alaser beam may form openings through the posterior thin walls and adherethe adhesive 35 to the lens 21 and to the human lens capsule.

In the embodiment of FIGS. 4 and 5, the lens 21 has a single opening 33extending therethrough between sides 27 and 29. The opening has no glueor adhesive therein and after the lens 21 is inserted into the eyethrough the incision 61, and centered on the anterior surface of thehuman lens the glue or adhesive 35 in a fluid state is injected to theposterior surface of the lens by way of a small tubular needle 71, of aninjection means 73, inserted through the opening 33. The lens 21 then iscompressed against the anterior capsular surface of the human lens.

In the embodiment of FIG. 6 and 7 the lens 21 has a single opening 33extending therethrough between sides 27 and 29 leading to a circularchannel 81 formed in its posterior side and employed to guide or directthe adhesive material 35 in a fluid state to its optimal location forfixation. In this embodiment the lens 21 may be inserted through theincision 61 and its posterior side 29 seated against the anteriorsurface of the human lens and the glue or adhesive in a fluid stateinjected with the device 71, 73 into the opening 33 for flow by way ofthe channel 81 for attaching the posterior side 29 of the lens 21 to theanterior surface of the human lens. The channel may not be completelycircumferential.

In one embodiment the intraocular lens 21 may be formed of a relativelyrigid plastic material such as polymethylmethacrylate (PMMA) to obtain athinner lens although it could be formed of a flexible plastic materialas disclosed in U.S. Pat. No. 4,573,998. The glue or adhesive 35employed must meet with the necessary and acceptable standards foradequate permanent bonding with intraocular biocompatibility and may bea cyanoacrylate glue or suitable silicone adhesive for a lens 21 formedof PMMA. When a laser beam is employed to adhere the glue or adhesive tothe human lens, the glue or adhesive will be a thermoplastic orthermosetting material.

There has been clinical experience in gluing contact lenses to theanterior corneal surface with reports of success up to five yearsduration. However, many attempts of gluing contacts met with onlylimited and temporary success due to undermining of the glued contact bythe surrounding corneal epithelium which then eventually sheds(desquamates) along with the overlying contact causing the previouslyglued contact to become nonadherent. However, it should be noted thatgluing as a permanent fixation mechanism for an epiphakic implant isexpected to be entirely acceptable since the anterior surface of thelens is an anatomically smooth, continuous capsule composed of a stablebasement membrane devoid of replicating cells, virtually nonmoving(except for the central change in radius of curvature associated withaccommodation), and relatively nonreactive with a low metabolism andlittle turn over of biological components. The anterior lens capsulerepresents and ideal biologic surface for adherence and fixation to anepiphakic implant.

The procedure for implantation of the epiphakic intraocular lens is amicrosurgical procedure requiring the use of an operating microscope.Anesthesia suitable for this procedure may be either generalendotracheal anesthesia or local anesthesia (such as retrobulbar orperiocular local anesthetic injection) which are commonly used for otherroutine types of intraocular surgery, such as cataract extraction.Similarly, the sterile technique and surgical principles involved arethose customarily used routinely for intraocular surgery such ascataract extraction.

Preoperative pupillary dilation is necessary and can be accomplishedwith several topical mydriatic ophthalmic medications, such as Mydriacyl1%, Cyclogyl 1% or Neosynephrine 10%. A typical preoperative regimenconsists of one drop of Cyclogyl 1% and one drop of Neosynephrine 10%,each medication being instilled in the operative eye a total of threetimes, the instillations being separated by about five minutes. Theinstillations should be completed approximately one half hour prior tosurgery.

After preoperative dilation has been accomplished, the patient ispositioned under the operating microscope, and the eyelids separatedwith an eyelid speculum. An incision through the surgical limbus,similar to that performed in cataract surgery, will provide a suitableentrance into the anterior chamber of the eye to allow for insertion ofthe implant into the eye. The usual location for the incision is in the12 o'clock position, but other limbal locations may be selected for anyparticular case, depending on the individual measurements and anatomy ofthe specific patient under consideration. A fornix-based conjunctivalflap is made to expose the underlying limbus in preparation for thelimbal incision, and the limbal area is cleaned and hemostasis isachieved. A usual cataract type of multi-planed limbal incision(commonly a biplaned incision) is made at the surgical limbus. Aninitial partial thickness corneoscleral incision is made with a scalpel,after which the anterior chamber is entered through the partialthickness incision with a scalpel, and the incision completed withcorneo-scleral scissors. The length of the incision is determined by theoverall size of the implant lens. Should the implant be of a rigid orsemi-flexible material, it is anticipated that an approximately 7 mm.incision will adequately allow passage and implantation of the implantlens (whose overall dimension is anticipated to be approximately 6 mm.).Should the implant be compressible or foldable, it is anticipated that aconsiderable smaller incision size might be acceptable, possibly assmall as 2 to 3 mm. in length Standard instruments such as tissueforceps will serve suitably to grasp the implant for implantation.Specifically designed implantation instruments may be employed,particularly if the implant is made of a soft material and can befolded.

After the implant is passed through the incision, it is then positionedand centered on the anterior surface of the lens (specifically theanterior lens capsule) with care taken not to damage the underlyingcapsule. The implant is centered and positioned so that the peripheralaspect of the implant toes not extend over or beyond the zonules to anysignificant degree as they insert onto the lens capsule peripherally.Prior to implantation, it is necessary to establish and maintain theanterior chamber with an air bubble, physiologic balanced salt solutionor possibly with visco-elastic material (such as Healon, Occucoat orViscoat), as is done in cataract surgery.

Once the epiphakic implant has been positioned on the anterior lenscapsule and centered, it then remains to make the implant adherent tothe underlying anterior lens capsule. This is accomplished as indicatedabove, by injection of the adhesive through a needle into theappropriate openings which are integral in the implant and designed toaccept and direct the liquid adhesive material to the desired location.An alternative technique is that the adhesive may be injected directlybetween the implant and lens capsule to provide adhesion. The adhesiveused in this manner (such as a cyanoacrylate type of glue) is in aliquid form and develops the adhesive bond after injection. The adhesiveshould be used as minimally as possible, and used primarily in theperiphery to render the peripheral aspect of the implant adherent. Theadhesive should not generally be used in the central optical axis areasince it might interfere with the optics of the implant and the humaneye lens.

A second type of adhesive may be employed as indicated above, thisadhesive being a thermoplastic or thermosetting type of adhesive whichbecomes activated and develops its adhesive bond upon the application ofenergy, such as heat or light energy particularly. This type of adhesiveis located, for the same reasons stated above, in the periphery of theimplant, as an integral part of the implant design. The energy source isthen directed and delivered to the site of the adhesive where theadhesive is activated and the adhesive bond between the epiphakicimplant and the underlying anterior lens capsule is produced. Varioussources of energy for adhesive activation may be employed. The laser isa particularly suitable energy source because of its ability to delivera variable, well controlled, and intense amount of energy to a small anddiscrete area. Depending on the particular configuration of the laserdelivery system, the energy may be directed and delivered from a sourceexternal to the eye (possibly mounted on and delivered through theoperating microscope), or through an instrument tip introduced into theeye. In the case of the probe tip introduced into the eye for energydelivery, the tip may need to be placed directly in contact with, orpossibly only in close proximity to the adhesive to be activated. Thatis to say, the tip may need to be directly physically in contact withthe adhesive in order to deliver sufficient energy for bonding. Theprobe tip energy source may not need to come in contact with the implantor adhesive, in all cases, but may provide sufficient energy from asmall distance away from actual contact with the implant and itsadhesive. As mentioned, a possible and very suitable location for alaser source is attached to and working in conjunction with theoperating microscope, which serves as its general guide for positioning.Activation of the laser or a probe tip is accomplished by a switchcontrolled by the operating surgeon.

Several spots or sites of adhesive bonding may be necessary to provideadequate adhesion and fixation of the implant to the underlying lenscapsule. Therefore, several sites of energy application, or adhesiveinjection as the case may be, may be necessary around the peripheralaspect of the implant. These bonding locations at the periphery of theimplant will be roughly circular or arcuate in shape, and basically willconform to the generally circular curvature of the implant periphery. Asa general principle, the amount of adhesive used, the number of bondingsites employed, and the amount of bonding energy used (for example if alaser system s: utilized) should all be kept to the minimum optimallynecessary to accomplish satisfactory bonding and stable fixation. Also,as mentioned previously, it is desirable to avoid adhesive in theoptical axis area of the eye if at all possible.

Once the sites of adhesive bonding are accomplished, and it is felt theimplant is suitably and satisfactorily fixated, the incision is closedin the standard method using surgical suturing techniques common tocataract surgery. The anterior chamber is evacuated of the previouslyplaced viscoelastic material or air bubble as is the surgeon's desire.The eye is then patched in the usual fashion common to the intraocularsurgery. The procedure is then complete.

In another embodiment, the implant lens 21 may have a peripheral andsurrounding edge or rim which is energy labile and upon being subjectedto a localized energy source such as heat from an Argon laser beam,transforms itself into a glue like or adhesive material which thenbecome adherent and bonds to the underlying human lens capsule.

It is important to minimize physical contact between the intraocularimplant lens 21 and the iris since it is known from clinical experiencethat similar contact between an intraocular lens implant and the iriscan results in "chaffing" with resultant pigment dispersion, glaucoma,and iritis, with the ultimate result of generalized intolerance of theimplant. Therefore, the periphery of the intraocular lens implant shouldbe made as thin as possible to avoid excessive physical contact to theposterior surface of the iris which lies immediately anterior to theanterior surface of the implant lens. Producing thin peripheral edgesmay require the use of multiple different peripheral curvatures similarto techniques used in contact lens manufacturing In addition to being asthin as possible, it is important that the peripheral edges be as smoothand rounded (non-sharp) to further minimize the trauma to any smallamount of implant/iris physical contact that may exist. However,thinness, smoothness, and roundness are not the only aspects ofperipheral edge design necessary for biocompatibility. Another featureis that in order to make the peripheral edge as minimally traumatic tothe overlying iris as possible, it is necessary to locate the edgejunction, that s the point of joining of the curves from the anteriorand posterior implant surfaces, as far posteriorly as possible. FIG. 10and 11 illustrate suboptimal edge profiles. In FIG. 10, the peripheraledge 31 is rounded but too thick. In FIG. 11, the peripheral edge 31 isthin but with the peripheral edge too anterior. FIGS. 12 and 13illustrate optimal edge profiles. In these figures, the peripheral edge31 of the intraocular lens 21 is located near the posterior surface andis rounded.

In addition, the peripheral edge of the lens 21 may be designed with"feet" or structures to elevate the central body of the implant lens offof the capsule of the human lens to enhance nutrition of a human lens.In FIG. 14, such "feet" are illustrated at 91 and they comprise aplurality of separate, spaced apart members 91 extending from theposterior surface 29 of the lens 21 for engaging the anterior surface43-1 of the human lens for seating the lens 21 against the human lens.The "feet" 91 may have dimensions radially such that small openings 33may be formed completely through the "feet" from their posterior sidesto the anterior side 27 of the lens 21 for receiving glue or adhesivefor bonding the lens 21 to the human lens as disclosed and described inconjunction with FIGS. 1, 2, 4, and 5. As a further alternative, theopenings 33-1 may be formed from the posterior side of the "feet" withthe anterior side of the lens 21 covering the openings. Such openingsmay be filled with glue or adhesive 35 for bonding the lens 21 to theanterior surface of the eye as disclosed and described in conjunctionwith FIG. 3. Both of these alternatives are shown in FIG. 14, althoughit is to be understood that only one or the other may be used.

One purpose of the "feet" 91 is to allow the lens 21 to have differentconfigurations such as plano-convex, rather than the concave-convexconfiguration of FIGS. 1-7. In this respect, the lens 21 may employ alight convergent (plus) or light divergent (minus) configuration for thecorrection of hyperopia and myopia respectively. Modern technology mayalso make possible the development of multiple strength bifocal andmultifocal optics for the correction of presbyopia either alone or inconjunction with the correction of hyperopia or myopia as is currentlybeing investigated in the optics of intraocular implants used after theremoval of a cataract. Also, the correction of astigmatism is at leasttheoretically, if not technologically possible.

In order to maintain sufficient nutrition to the human lens, nutrientscontained in the aqueous humor, in particular, glucose, (but alsooxygen, calcium and other substances) must have access to the anteriorcapsular surface of the human lens. This can be accomplished by use ofthe "feet" 91 which elevate the central body of the implant lens off ofthe surface of the capsule of the human lens by means of the peripheralfeet or elevation structures 91. It is anticipated that this type ofseparation may be necessary if a material such as PMMA with its knownlow permeability is used in a substantial portion of the implant lens.Since the surface of the normal crystalline human lens is soft, theperipheral "feet" 91 may have to be relatively wide radially and alsorelatively long circumferentially to prevent the "feet" from sinkinginto depressions on the soft and pliable capsular surface of the humanlens and hence to prevent any negating of the intended elevating effectof the "feet" 91.

Another method of increasing implant permeability is to provide theimplant with perforations extending through the lens 21 between itsanterior and posterior sides 27 and 29 at desired positions to allow forthe passage of aquous through the implant such as has been accomplishedin the previously mentioned polysulfone intracorneal implants beingdeveloped by Choyce. As an example, one perforation is shown at 24 inthe lens of FIG. 13. It is important that central perforations(microperforations most likely), do not affect the optical performanceof the implant lens.

In another embodiment, the implant lens may be formed from a materialthat is naturally permeable to the nutrient required by the human lensfor normal metabolism. This may be accomplished by utilizing known gaspermeable materials such as cellulose acetate, butyrate,siloxanyl/methacrylete combinations, silicone resins or hydrogels, etc.,surrounded by a more energy resistant and resilient rim 131 such asshown in the embodiment of FIG. 16. In this embodiment, the permeablecentral optical portion 121 is surrounded by and joined to anappropriately thin carrier ring 131. The carrier ring 131 may have theopenings 33 or 33-1 formed therethrough or therein for receiving theglue or adhesive for bonding purposes. Since the intraocular lens may besubjected to high energy levels, it is anticipated that the appropriatematerial for the implant lens be sufficiently energy resistant(thermo-resistant in the case of high energy heat application from asource such as Argon laser) to prevent degredation of the material.Again, this may require an implant design consisting of a centralpermeable optical element required for maintenance of human lensmetabolism, joined to a more durable and energy resistant ring as shownin FIG. 16.

The overall shape of the implant lens preferably is generally circularto maximally fill the optical zone of the zonular free central lenssurface. This has the advantage of maximally eliminating edge glare inthe event of pupillary dilation in dim lighting conditions. Thegenerally circular configuration, however, will have the theoreticaldisadvantage of covering the maximal surface area of the lens capsulethereby possibly producing the greatest alteration of normal lensmetabolism. In order to avoid this problem, the shape of the intraocularlens, instead of being generally circular, may be elliptical,triangular, or square, or other shape as desired to maximallycounterbalance the opposing concerns of edge glare and the maintenanceof normal lens metabolism.

In considering the approach to proper fitting of the epiphakic implantto the anterior surface of the human lens, consideration must be givento both the convex curvature of the anterior capsular surface of thehuman lens and to the concave posterior curvature of the epiphakicimplant. The fitting theories described by Kelman (U.S. Pat. No.4,769,036) and Blackmore (U.S. Pat. No. 4,585,456) both consider anepiphakic implant with a posterior concave surface that is fit in directcontact with the convex anterior capsular surface of the human lens,particularly centrally.

With the epiphakic implant resting substantially on the center of thelens, the physical presence of the implant may impede the ability of thehuman lens to change its shape. Specifically, the physical presence ofthe implant resting on the convex anterior capsular curvature of thecentral portion of the human lens may prevent the anterior lens surfacefrom bowing or curving forward as it naturally does duringaccommodation. It is a known physiologic fact that accommodation in thehuman lens is accomplished by the human lens changing its shape,particularly the shape of the anterior capsular surface of the lens.Even more specifically, the primary location of the change of the shapeof the human lens, which accounts for a change in focus accompanyingaccommodation, is the central portion of the anterior capsule. The majorconfigurational change occurs in the central capsular area because thecentral anterior capsule is thinner and therefore more pliable andcapable of an alteration of configuration. Physiologic studies show thatthe change in lens power that is produced during accommodation is almosttotally due to the change in configuration of the central part of theanterior capsule. It is known that the central anterior capsule bulgesforward during accommodation producing the increased optical power inthe lens. With the physical presence of a lens resting on the center ofthe anterior surface of the human lens, the ability of the lens capsuleto change shapes may be significantly impeded, if not eliminatedaltogether, thereby diminishing or possibly eliminating the ability ofthe lens to change its focuses and thereby accommodate. It is thispotential decrease or complete loss of accommodation that is the majordisadvantage of fitting the implant in direct contact with the centralarea of the lens capsule.

Kelman (U.S. Pat. No. 4,769,085) describes his implant with "theposterior surface of the optic portion of such lens with a concave shapesubstantially conforming in curvature to the convex shape determined forthe anterior surface of the natural lens of the eye when the latter isin is flattest natural condition".

The Kelman technique of fitting the implant to the anterior capsularsurface when the capsule is in its flattest (unaccommodating)configuration greatly increases and compounds the problems of preservingaccommodation because the implant is placed on the lens when it is leastaccommodating, thereby requiring the maximal configurational change inthe lens to accomplish even the most modest amounts of accommodation. Asmentioned, this anterior capsular forward bowing configurational changemust be made directly against the unyielding physical presence of theimplant which rests directly on the central capsule.

With the above mentioned concern for the preservation of accommodationin mind, there is here provided a new and novel fitting theory andtechnique and epiphakic implant configuration in which the centralaspect of the epiphakic implant is constructed so that the concaveposterior curvature vaults above the central aspect cf the human lens,thereby leaving a central space between the concave posterior curvatureof the epiphakic implant and the convex anterior capsular surface of thehuman lens centrally. The periphery of the implant will still be insubstantial contact with the convex anterior capsular surface, however,and the central portion is vaulted thereby leaving a small separation orspace. Referring to FIGS. 17 and 18, the central portion 29-1 of theposterior side 29 of the lens 21 is vaulted from the plane 34 of itsperipheral edge 31 sufficient that the central portion 29-1 of theposterior side 29 of the lens 21 will be spaced from the anteriorcapsular surface 43-1 of the human lens 43 when its periphery 31 seatsagainst and engages the anterior capsular surface of the human lens.This fitting approach and epiphakic configuration has the advantage ofallowing the human lens to change its shape naturally, thereby allowingand providing for natural accommodation. It also has the advantage ofproviding a space and compartment through which the aqueous humor maypass from between the bonding spots thereby providing access foressential nutrients from the aqueous humor to the anterior surface ofthe lens. Also, the change in configuration of the anterior surface ofthe human lens which occurs naturally with accommodation will at timesshallow and then at other times deepen this small chamber space, therebyproviding a "pumping" mechanism to move fluid in and out of the space.This also serves to enhance aqueous humor circulation across this areaof the lens, which would otherwise be covered by the implant. It may benecessary to use peripheral holes in the implant to enhance andfacilitate aqueous flow. It is anticipated that a space of approximately0.5 mm (between the surface 29-1 of the lens 21 and the anteriorcapsular surface 43-1 of the human lens) will be sufficient tocompletely preserve accommodation, although a smaller or possibly agreater space may be necessary as will be determined from clinicalexperience.

In the embodiment of FIGS. 17 and 18, the lens 21 near its peripheraledge 31, where it seats against the anterior surface of the human lens,may have the openings 33 or 33-1 formed therethrough or therein forreceiving the glue or adhesive for bonding purposes as describedpreviously. Both of these features are shown in FIG. 18, although it isto be understood that only one or the other may be used. The embodimentof FIGS. 7 and 18 has advantages over the embodiment of FIGS. 14 and 15in that it provides more support and seating surface than the feet 91,thereby providing for more fixation surface and avoiding or minimizingsinking or depression of the lens implant into the soft capsular surfaceof the human lens. In the embodiment of FIG. 19, vaulting of the lensimplant 21 at and near the edge is reduced and the angle of vaultingspaced inward from the edge toward the axis is greater in order tominimize contact of the lens with the iris.

Thus there is provided in the embodiment of FIGS. 17, 18, and 19 a new"vaulting" epiphakic implant fitting technique and configuration inwhich the posterior implant surface is rendered sufficiently concave tovault off the anterior surface of the human capsule, providing a spacebetween the convex anterior capsular surface of the human lens and theconcave posterior surface of the implant. This "vaulting" allowsconfigurational changes to occur naturally in the central part of theanterior capsular surface or the human lens and thereby preservesnatural accommodation of the human lens. The "vaulting" also providessuperior access to the lens for the nutrient supplying aqueous humor.

Thus there is herein disclosed a new and unique type of refractivecorrection intraocular lens implant which is designed and intended forimplantation upon and fixation to the anterior capsular surface of thehuman crystalline lens. Fixation is uniquely accomplished by directadhesion to the anterior capsule of the human crystalline lens throughthe employment of glues or adhesive materials, or by the application ofenergy directly to the implant material itself, to produceimplant-to-lens adhesions.

The overall dimensions of the implant lens are specifically and uniquelydesigned to be such that when the implant lens is positioned properly onthe anterior surface of the human lens, its overall edge-to-edgedimensions are such that it remains central to or minimally overlappingthe zonular attachments of the human crystalline lens. Furthermore, theimplant lens periphery should be sufficiently thin, smooth, and roundedas to avoid an unacceptable amount of mechanical contact to thesurrounding tissues, particularly the iris. In addition, the implantlens is constructed by design and materials to avoid substantiallyinterfering with the normal metabolism of the human lens. The uniqueintraocular lens disclosed with its novel features of adhesive capsularfixation and physiologically appropriate dimensions, design, andmaterials is expected to result in an acceptably biocompatible and welltolerated refractive correction device for the human eye.

An intraocular lens implant is used to provide optical power within theeye which is lost after removal of a cataractous lens from the humaneye. Generally, a particular desired overall refractive strength for theeye can be accomplished by making preoperative calculations usingmeasurements determined from the corneal curvature and the axial lengthof the eye, and then based on these calculations, implanting a lens of aparticular specified optical power which will then give the eye thedesired overall optic power or refraction (myopic or hyperopic). It doeshappen occasionally, however, that the refractive power of the eye isfound to be considerably different postoperatively from what wascalculated, anticipated, and desired preoperatively. That is to say, theintended optical refractive result of the eye after removal of thecataract and implantation of the intraocular lens is considerablydifferent from that expected and hoped for. This undesirablecircumstance of postoperative refraction being considerably deviant fromthe desired refraction can be sufficiently extreme and intolerable as torequire correction of the optical situation. This may be because ofsignificant optical imbalance between the operated eye and the oppositeeye, or simply because the optical correction is sufficiently strong asto be undesirable in and of itself. In fact, the presence of anundesirable optical result is one of the leading reasons for the need toreplace a posterior chamber intraocular lens.

The only technique currently available for definitive correction of thisundesirable optical condition is to remove the existing intraocular lensimplant and replace it with an implant with a more proper optical power,which then results in restoration of the eye to the desired overalloptical power and refraction. Removing the intraocular lens implant,however, can be an extremely difficult and traumatic operation to theeye and risks great damage to the eye in many cases. In fact, removingthe intraocular lens can be sufficiently hazardous in some people suchthat it is avoided for fear of damage to the eye resulting in possiblecomplete loss of vision and blindness. This is because, in order toremove an intraocular lens, especially a posterior chamber intraocularlens, it is necessary to free the implant from the adhesions that havedeveloped around the implant, particularly around the haptic fixationmembers from the capsule, iris and ciliary body of the eye.

Because it is technically difficult and potentially dangerous to the eyeto remove an existing intraocular lens, particularly a posterior chamberintraocular lens with associated adhesions, it is desirable to have atechnique of changing the intraocular lens power without having toremove the existing intraocular lens. It is an object of the inventionto provide such a means and process by use of an intraocular lensimplant comprising essentially an optical portion which is placed withinthe eye directly on the optical portion of the already implantedintraocular lens. This process will eliminate the need to remove thealready implanted intraocular lens.

The second implant which is placed directly on the optic of the alreadyimplanted intraocular lens will have an optical power such that itsoptical power, in combination with the already implanted intraocularlens, will combine to provide the overall desired optical power andrefraction of the eye. This can be determined by using the known opticalpower of the eye with the implanted intraocular lens and creating theoptical power of the second implant specifically for optical correctionof the known optical deviation. Since this implant is placed directly onthe optic of the already implanted intraocular lens it need not have anymeans of tissue fixation itself. It is simply placed directly upon theoptic of the already implanted intraocular lens and made to fixate onthe optic of the already implanted intraocular lens by one of severalmechanisms including:

1. Adhesives.

2. Mechanical means including means for clipping around the optic edgeor through existing optic holes of the previously implanted lens, shouldthey be present.

3. Mechanical means for fixation around the haptic of the alreadyexisting implanted lens.

By this means of optically altering the overall power of the alreadyimplanted intraocular lens, the optical correction can be performedwithout requiring removal of the existing implant and avoidingtechnically difficult and potentially very damaging surgery which mayotherwise be necessary to correct the situation. It can therefore beseen that this second implant placed on the optic of the alreadyimplanted intraocular lens will provide a means for optical poweralteration and a safer process than exists at this time. It is also seenthat in addition to simply correcting the optical power (by eithermaking the eye more or less myopic or hyperopia), the second implantoptic may contain bifocal or multifocal optics and thereby providebifocal or multifocal capability to the already implanted intraocularlens which does not have multifocal (bifocal) capability. An additionalneed for optical change is to add the capability of bifocal ormultifocal optic function to the already implanted intraocular lens,allowing the patient to minimize or completely eliminate the use ofglasses. Correction may also be made for astigmatism.

This procedure can be performed on an already implanted intraocular lensin either the anterior chamber or the posterior chamber. Becausegenerally relatively small amounts of optical power correction arerequired (relative to the overall optical power of the eye), the implantmay be relatively thin compared to the optic of the already implantedintraocular lens. Because of its thin nature, if it is made of foldablematerials, the implant may be folded or "rolled" and implanted through avery small incision. This will minimize surgical trauma even further. Itis anticipated that this implant will be capable of fixation on theoptic of the already implanted intraocular lens even if the anteriorsurface of the optic of the already implanted intraocular lens ispartially covered by tissue such as anterior capsule peripherally.

Referring now to FIG. 20, there is disclosed an artificial intraocularlens comprising a transparent optic body 221 having two fixation loopsor haptic members 223 extending outwardly from opposite sides of theperiphery of the lens body 221. The fixation members 223 are identicalin shape but are asymmetrically arranged relative to the lens body 221for supporting the lens body in the eye as disclosed in U.S. Pat. No.4,418,431 which is incorporated into this application by reference. FIG.21 is a simplified partial cross-sectional view of any eye with the lensof FIG. 20 implanted in the anterior chamber. In FIG. 21, referencenumeral 231 defines the seleral spur; 233 the posterior capsule; and 235the ciliary body. In FIG. 21, the haptics 223 are seated in the area ofthe seleral spur such that the lens is implanted in the anteriorchamber.

In FIG. 22, the lens of FIG. 20 is implanted in the posterior chamberwith its fixation members 223 in the ciliary sulcus. In FIG. 23, thelens of FIG. 20 is implanted in the posterior chamber with its fixationmembers 223 in the posterior capsular bag. In FIGS. 20-23, the lens bodyis convex-convex.

The artificial intraocular lens previously implanted into the eye asdisclosed for example in FIGS. 21, 22, and 23, can be optically alteredand corrected by attaching a second intraocular lens to the anteriorsurface of the optic 221 of the implant either with glue or adhesive orwith clips as now will be described. The operative procedure is the sameas that disclosed above wherein an artificial intraocular lens wasdescribed as being inserted into the eye and seated on and attached tothe anterior surface of the natural lens of the eye. In FIGS. 24-27,four artificial intraocular lenses 241, 251, 261 and 271 are shown asseated against and attached to the posterior surface of the optic 221 ofthe previously implanted lens with the use of wells 33 or 33-1 and glueor adhesive as described previously. If desired, a channel similar tochannel 81 of FIGS. 6 and 7 may be formed on the posterior side of thelens 241, 251, and 271 of FIGS. 24-26 in communication with the aperture33 to guide the adhesive In the alternative, a tubular needle may beemployed to inject the fluid adhesive between the periphery of the firstand second implants without the use of the wells 33 or 33-1 as describedabove. The second implant may be formed of the same material as thefirst implant, that is PMMA as disclosed above, silicone materials, andvirtually any material already used for intraocular lens implants.Referring to FIG. 24, the implant 241 has an anterior curvature formyopic correction. In FIG. 25, the lens 251 has an anterior curvaturefor correction of hyperopia. In FIG. 26, the lens implant 271 containsdefraction optics on its anterior surface. In FIG. 27, the lens implant261 has a diameter smaller than that of the previously implanted lens221.

Referring row the FIGS. 28, 29, and 30, there are disclosed intraocularlens implant members 291, 301, and 321 which employ spaced apart clipsat their periphery for clipping the second implant to the first implant.The implants 291, 301, and 321 also may be formed of the same materialthat lenses 241, 251, 261, and 271 are formed as described above such asPMMA. In FIG. 28, the implant 291 has a plurality of spaced apartclipped clips 293 formed at its peripheral edge for clipping around theedge and onto the posterior surface of the implant 221. The clips 293are resilient and can be sprung outward to allow the clips 293 to fitaround the lens 221 and then released to allow the clips 293 to securethe lens 291 to the lens 221. In FIG. 29, the previously implanted lens221 may have apertures 227 formed therethrough at selected positions asis common with intraocular implants lenses, for example as disclosed inU.S. Pat. No. 4,418,431, and the lens 301 has a plurality of spacedapart clip members 303 at its peripheral edge with pegs 305 which may besprung outward for insertion about the edge of implant 221 and thenreleased such that the pegs 305 enter the apertures 227 for holding thelens 301 to the lens 221. In FIG. 30, the lens 321 has a plurality ofspaced apart peg members or rods 323 extending from its posterior sidenear its peripheral edge with resilient flanges 327. These peg membersmay be inserted through the apertures 227 with the flanges 327 movedbackward against the peg members 323 and when the flanges are movedthrough the apertures 227 to the posterior side of the lens 221, theyspring outward to hold the implant 321 against the implant 221. As analternative the pegs 223 may be wedge shaped (with smaller free ends)and wedged into the apertures 227 for attaching the implant 321 to theimplant 221. In addition, the pegs 223 may be formed of hardenedadhesive for insertion into the apertures 227 and attached to theimplant 221 with energy from a laser for attaching the implant 321 tothe implant 221.

Referring to FIG. 31, the implant lens 331 may be formed of the sametransparent material as described above, such as PMMA, however, itsposterior surface 331-1 is formed such that there is a space 332 betweenthe central portions of the posterior and anterior surfaces of thelenses 331 and 221 when the peripheral edge of the lens 381 engages andis seated against the peripheral edge of the implant 221 and attached inplace for example, by adhesive using the wells 33 or 33-1 or injected bythe use of a tubular needle between the two peripheral edges. The space332 between the two optic members 231 and 221 will contain the aqueousof the eye eliminating the need for precise matching curvatures of theoptic devices. Microperforations may be formed through the lens 331 nearits peripheral edge, one of which is shown at 334 to allow for passageof the aqueous to the space 332.

FIG. 32 illustrates a transparent optic member 341 of an antificialintraocular lens having small resilient hooks or clips 343 extendingfrom its peripheral edge which are hooked around the haptics 345 of anartificial intraocular lens 347 previously implanted in the eye toattach the optic member 341 to the optic member 347 with the posteriorside of the optic member 341 facing and engaging the anterior side ofthe optic member 347. The lens 347 is implanted in the eye after thenatural human lens is removed and is held in place in the eye by thehaptics 345.

Although the second artificial lenses of FIGS. 24-31 were described asbeing attached to the previously implanted lens of the type shown inU.S. Pat. No. 4,418,431, it is to be understood that the secondartificial lens of FIGS. 24-31 may be attached to previously implantedlenses having different optic body and haptic shapes.

As described above, the second implants of FIGS. 24-32 will be implantedthrough a limbal incision as is commonly used in cataract andintraocular lens surgery. The fixation surgical technique will varydepending on the particular fixation mechanism employed by the implant.The procedure will be performed in the usual sterile fashion forintraocular surgery in accordance with the principles of such surgery asdescribed above with respect to the attachment of an artificialintraocular lens to the natural lens of the human eye.

Thus in the embodiments of FIGS. 24-32, as described above, there areprovided artificial intraocular implants which have optical power whichrests on the optic surface of an already implanted intraocular lens foroptically changing the overall power of the previously implanted lensthereby correcting an existing undesirable optic situation. It is alsoseen that such second implants can have the ability to add bifocalfunction to the previously implanted intraocular lens which does nothave bifocal function previously. It is seen that fixation of the secondimplant may be either by adhesive to the previously implanted opticsurface or with "clip" means located around the optic edge; throughexisting optic holes; or around the adjacent haptics of the alreadyimplanted intraocular lens.

I claim:
 1. An artificial intraocular lens for implantation in the eyeof a human, comprising:a transparent optic member having an optical axisand anterior and posterior sides transverse to said optical axis andextending outward from said optical axis to a peripheral edge, saidtransparent optic member being adapted to be inserted into the eyethrough an incision formed in the eye and seated against and attached tothe anterior surface of the natural lens of the eye with its posteriorside facing the anterior surface of the natural lens of the eye, themaximum dimension of said artificial intraocular lens in a planetransverse to said optical axis being such that when said artificialintraocular lens is seated against the anterior surface of the naturallens of the eye in substantial optical alignment therewith, saidartificial intraocular lens does not have any structure which extendsbeyond the peripheral edge of the natural lens of the eye, at least oneaperture formed through said artificial intraocular lens near saidperipheral edge and extending between said anterior and posterior sidesof said artificial intraocular lens for receiving an adhesive for usefor attaching said artificial intraocular lens to the anterior surfaceof the natural lens of the eye, and a channel formed into saidartificial intraocular lens from said posterior side and extending tosaid opening for guiding said adhesive when received through saidopening.
 2. An artificial intraocular lens for implantation in the eyeof a human, comprising:a transparent optic member having an optical axisand anterior and posterior sides transverse to said optical axis andextending outward from said optical axis to a peripheral edge, saidtransparent optic member being adapted to be inserted into the eyethrough an incision formed in the eye and seated against and attached tothe anterior surface of the natural lens of the eye with its posteriorside facing the anterior surface of the natural lens of the eye, themaximum dimension of said artificial intraocular lens in a planetransverse to said optical axis being such that when said artificialintraocular lens is seated against the anterior surface of the naturallens of the eye in substantial optical alignment therewith, saidartificial intraocular lens does not have any structure which extendsbeyond the peripheral edge of the natural lens of the eye, and at leastone opening formed into said artificial intraocular lens from saidposterior side for receiving an adhesive for use for attaching saidartificial intraocular lens to the anterior surface of the natural lensof the eye, said artificial intraocular lens comprising structureextending across said opening at one of said sides such that saidopening does not extend through said artificial intraocular lens.
 3. Amethod of implanting an artificial intraocular lens into a human eyefrom which the natural lens has previously been removed and a firstartificial intraocular lens has been implanted, comprising the stepsof:providing a second artificial intraocular lens, forming an incisionin the eye, inserting said second artificial intraocular lens throughsaid incision, into the eye, and using an adhesive to attach said secondartificial intraocular lens to said first artificial intraocular lens insubstantial optical alignment therewith.
 4. The method of claim 3wherein laser energy is employed to attach said second artificialintraocular lens to said first intraocular lens with the use of saidadhesive.
 5. An artificial intraocular lens for implantation in the eyeof a human, comprising:a transparent optic member having an optical axisand anterior and posterior sides transverse to said optical axis andextending outward from said optical axis to a peripheral edge, saidtransparent optic member being adapted to be inserted into the eyethrough an incision formed in the eye and seated against a previouslyimplanted artificial intraocular lens in the eye and attached to saidpreviously implanted artificial intraocular lens with the posterior sideof said transparent optic member facing the anterior side of saidpreviously implanted artificial intraocular lens, the anterior side ofsaid transparent optic member being shaped for optically correcting saidpreviously implanted artificial intraocular lens in a desired manner atleast one aperture formed through said transparent optic member nearsaid peripheral edge and extending between said anterior and posteriorsides of said transparent optic member lens for receiving an adhesivefor use for attaching said transparent optic member to the anteriorsurface of said previously implanted artificial intraocular lens, and achannel formed into said transparent optic member from said posteriorside and extending to said opening for guiding said adhesive whenreceived through said opening.
 6. An artificial intraocular lens forimplantation in the eye of a human, comprising:a transparent opticmember having an optical axis and anterior and posterior sidestransverse to said optical axis and extending outward from said opticalaxis to a peripheral edge, said transparent optic member being adaptedto be inserted into the eye through an incision formed in the eye andseated against a previously implanted artificial intraocular lens in theeye and attached to said previously implanted artificial intraocularlens with the posterior side of said transparent optic member facing theanterior side of said previously implanted artificial intraocular lens,the anterior side of said transparent optic member being shaped foroptically correcting said previously implanted artificial intraocularlens in a desired manner, at least one opening formed into saidtransparent optic member from said posterior side for receiving anadhesive for use for attaching said transparent optic member to theanterior surface of said previously implanted artificial intraocularlens, said transparent optic member comprising structure extendingacross said opening at said anterior side such that said opening doesnot extend through said transparent optic member.
 7. An artificialintraocular lens for implantation in the eye of a human, comprising:atransparent optic member having an optical axis and anterior andposterior sides transverse to said optical axis and extending outwardfrom said optical axis to a peripheral edge, said transparent opticmember being adapted to be inserted into the eye through an incisionformed in the eye and seated against a previously implanted artificialintraocular lens in the eye and attached to said previously implantedartificial intraocular lens with the posterior side of said transparentoptic member facing the anterior side of said previously implantedartificial intraocular lens, the anterior side of said transparent opticmember being shaped for optically correcting said previously implantedartificial intraocular lens in a desired manner, structural meansextending from said transparent optic member for engaging saidpreviously implanted artificial intraocular lens for attaching saidtransparent optic member to said previously implanted artificialintraocular lens, said structural means comprises peg means extendingfrom the posterior side of said transparent optic member near itsperipheral edge for insertion into apertures formed through saidpreviously implanted artificial intraocular lens.
 8. An artificialintraocular lens for implantation in the eye of a human, comprising:atransparent optic member having an optical axis and anterior andposterior sides transverse to said optical axis and extending outwardfrom said optical axis to a peripheral edge, said transparent opticmember being adapted to be inserted into the eye through an incisionformed in the eye and seated against a previously implanted artificialintraocular lens in the eye and attached to said previously implantedartificial intraocular lens with the posterior side of said transparentoptic member facing the anterior side of said previously implantedartificial intraocular lens, the anterior side of said transparent opticmember being shaped for optically correcting said previously implantedartificial intraocular lens in a desired manner, means extending fromsaid transparent optic member for insertion into apertures formedthrough said previously implanted artificial intraocular lens forattaching said transparent optic member to said previously implantedartificial intraocular lens.
 9. An artificial intraocular lens forimplantation in the eye of a human, comprising:a transparent opticmember having an optical axis and anterior and posterior sidestransverse to said optical axis and extending outward from said opticalaxis to a peripheral edge, said transparent optic member being adaptedto be inserted into the eye through an incision formed in the eye andseated against means in the eye in substantial optical alignment withthe eye, at least one opening formed in said transparent optic membernear said peripheral edge for receiving an adhesive for use forattaching said transparent optic member to said means in the eye, andsaid opening comprises an aperture extending through said transparentoptic member between said anterior and posterior sides of saidtransparent optic member, and a channel formed into said transparentoptic member from said posterior side and extending to said aperture forguiding said adhesive when received through said opening.
 10. Anartificial intraocular lens for implantation in the eye of a human,comprising:a transparent optic member having an optical axis andanterior and posterior sides transverse to said optical axis andextending outward from said optical axis to a peripheral edge, saidtransparent optic member being adapted to be inserted into the eyethrough an incision formed in the eye and seated against means in theeye in substantial optical alignment with the eye, at least one openingformed in said transparent optic member near said peripheral edge forreceiving an adhesive for use for attaching said transparent opticmember to said means in the eye, said opening is formed into saidtransparent optic member from said posterior side for receiving anadhesive for use for attaching said transparent optic member to saidmeans in the eye, said transparent optic member comprising structureextending across said opening at said anterior side such that saidopening does not extend through said transparent optic member.